Production of the metal elements of sliding clasp fastener strips



shaggy 14;, iggbfis w GERLACH fi ijfi g PRODUCTION OF THE METAL ELEMENTS OF SLIDING CLASP FASTENER STRIPi Filed Feb, 18, 1953 PRODUGTION (OFF THE METAK; ELEMENTS @F SLIDING CLASP FASTENIER STRIPS Wilhelm Gerlach, ll ranhfort-on-thell lain, Germany, assignor to Erwin Paul Dieseldoriit',

(Cuban, Guatemala Application February 18, 1933, Serial No. 657/154 in Germany February 22, 1932 .2 claims. on. 153 l) This invention relatesto the production of the metal elements of sliding clasp fastener strips. These strips consist of suitable material, usually cloth, on which the aforesaid metal ele ments are mounted in spaced relationship, two of such strips together with the sliding clasp forming a so-called zip or lightning fastener as now commonly employed in handbags, articles of clothing, tobacco pouches and other articles where two edges are required to be brought together. These metal elements include two limbs which embrace the edge of the cloth strip, the metal elements being secured on the cloth strip by pressing the outspread limbs towards one another. These 'metal elements have previously been produced by stamping them out of a metal band with the limbs inan outspread condition, an appreciable quantity of metal having therefore to be removed in order to form the space between the outspread arms and thus giving rise to waste. Moreover, even if the width of the metal band were equal to the height or breadth of the element with its outspread arms further waste would be occasioned by reason of the fact that metal would have to be removed on the outsideof the limbs. cost of production, which increase is of course greater the more valuable the material of which the elements are made.

The chief object of the present invention is to produce metal elements for sliding clasp fastener strips with as little waste of material as is reasonably possible.

According to the invention, this is attained by making the elements from contiguous portions of appropriate length out from a metal strip of a width. equal to the height or width of the elements with the limbs in a closed condition, the limbs being formed in that condition by slitting or perforating the metal of the strip and being brought into a condition for receiving the edge of the cloth or like strip by spreading them apart, the spreading being effected before the separa tion of the element from the strip. The separation of each member from the metal strip need not be efi'ected until after it has been secured on the cloth strip.

In order that the invention may be clearly understood and readily carried into effect, it will now be described by way of example with reference to the accompanying drawing, in which:,-

Figure 1 is a plan view of a metal strip illustrating the method of producingthe metal elements according to the invention.

This waste esults in an increase in the Fig. 2 shows a metal element after it has been secured on a cloth strip. The width of the metal strip l of Fig. l is equal to the height of the elements which are to be produced. The strip is slit and perforated as 5 shown at la, the slits ta extending at right an= gles to the edges 8, 9 of the metal strip into one of which edges 9 they open at one end. This slit ting and perforating leads to the formation of the limbs 2 and 2a, which are subsequently to em- 10 brace the cloth strip. The shape of the slits or perforations depends on the shape of the cloth strip which is to be provided with the elements.

They may be as illustrated or, for example, the

slit may be corrugated, or a pear-shaped opening may be provided. The metal elements mustrated in Fig. l are intended for use with a cloth strip having an edge or head of enlarged circular cross-section. A head of a diiferent shape could be employed as also could a cloth strip having a plain, i. e, unbeaded, edge. The elements are produced from the slit and perforated metal strip by cutting it along transverse lines which are 111- dicated in the drawing by the dotted lines 3a, one separation along a line 35a producing an edge of two elements and the slits and perforations being spaced apart accordingly. Before this separation is aifected, however, the limb 2 at the end of the metal strip is bent away from the limb 2a. to an extent sufiicient to allow for the passageof the element over the edge of the cloth strip, by means of a wedgedlke tool which is forced into theopen end of the slit la.

Metal elements produced in accordance with the method illustrated in Fig. 1 are more particularly suited for use when they are to be secured on the cloth strip by hand, the burr which may be present on the edges produced at the lines of separation 3a and any which may also exist on the edges 8, 9 being first removed by agitating 40 the elements, for example, in a rotating drum. The edges 8, S of the metal band are, however preferably previously smoothed. The presence of burr on the edges produced at the lines of separation 3a, i. e. on the edges of the elements which are parallel to the slit, would cause roughness of operation of the sliding clasp and also spoil the appearance of the fastener strips provided with the elements.

When the metal-elements are to he produced and secured on the cloth strip mechanically, as, for example, in the manner described in the specification of British Patent No, 379,762, the removalof burr by agitating the elements as aforesaid is not possible and in fact a satisfactory 2 method of removing burr in such a case is not known. For this-reason, zip or lightning fastener strips on which the metal elements have been placed by hand have hitherto been given preference to those in which this has been done mechanically.

Fig. 2 shows one of the metal elements securedto a cloth strip 5. The metal element is placed over the strip so that the limbs 2 and 2a embrace it and these are then pressed towards one another so that the element grips the strip. The edges 6 and 'l or this element are the edges without burr.

The metal strip might, for example, be composed of a non-oxidizable and comparatively cheap and soft metal such as brass and be coated electrolytically with nickel or a precious metal. The metal strip may, however, have a coating of rubber, enamel, paint, lacquer or the like.

The formation of the slit and perforation need not take place at the same time as the separating and spreading, for the metal strip may be slit and perforated at the appropriate intervals along its whole length and then fed to a separating and spreading tool.

It is to be understood that metal elements produced in accordance with the invention may be provided with projections and recesses for interengagement in the closed position of the fastener strip as is usual, although the formation of these has not been described or illustrated.

1. The method for the production of metal elements for sliding clasp fasteners from strips, which consists in cutting in a metal strip of a width equal to one of the plane dimensions of the finished element, limb forming slits disposed 10 substantially in parallel spaced relation in the strip and opening through one lateral edge thereof, and alternately and successively spreading the limbs of said element portions of the strips and severing the same from end to end of the 15 strip.

2. The method of producing sliding fastener elements from a metal strip, which consists in cutting parallel spaced slits in a metal strip of a width equal to one of the plane dimensions of 20 a finished element and with the slits opening through one longitudinal edge of the strip and spaced apart a distance to provide one slit in each element when severed from the strip, opening the slits oi the successive end elements, and 25 severing the elements successively from the strip.

WILHELM GERLACH. 

